Ran across this on the internet.
It's a weapon that uses centrifugal force instead of conventional gunpowder to fire ammunition.
Benefits it boasts are:
1) No muzzle flash (stealthy)
2) Jam proof
3) No Recoil
4) Self Cleaning
5) Silent
... and the list goes on.
Seems to be quite an interesting concept. Take a look at the link below. The complete article is quite long so I shall not post it.
http://www.defensereview.com/modules.php?name=News&file=article&sid=526